Evolution of Light
Lighting technology has developed from:
Electric lighting is electric energy converted into light. We use terms globe, bulb, lamp, light fitting, etc. An electric current is passed through the globes filament e.g. a wire or a gas, thus emitting heat and light.

Fire oil paraffin - candles Hurricane lamp - incandescent globe high discharge intensity lamps - CFL halogen LEDs fibre optics (the future)

Lumen Efficiency
Lumen Efficiency refers to useful conversion of power to light
It is measured in- Lumen / Watt
Incandescent has the lowest 90% energy wasted as heat
Fluorescent lumen is double that of incandescent 10% energy wasted as heat
Low Pressure Sodium has the highest efficiency Road lights
Warm white has better efficiency than Cool white
Lumen efficiency over the years have increased due to innovations in all types except incandescent
Lamp life
Lamp life will be determined by the design of the lamp, the voltage going through the amp as well as the material used to construct the lamp. In general, though, these are the average life expectancies of the different lamp types. Note that CFLs and fluorescent lamps last longer because they are more efficient.
| Light |
Average Light |
|
High Pressure |
10,000 - 40,000 |
|
Low Pressure |
16,000 - 36,000 |
|
Mercury |
12,000 - 24,000 |
|
Metal |
5,000 - 30,000 |
|
Fluorescent |
12,000 - 20,000 |
|
Compact |
4,000 - 10,000 |
|
Incadesce |
750 - 2,000 |
ESL- Component- Product

** Fact sheet on mercury in CFL